Network protection using network coding

Abstract

A method for protecting against link failures in a communications network having a plurality of paths between senders and receivers is provided. The method includes sending data units by the senders over the communications network on working circuits, applying network coding to form a combination of data units from data units from a plurality of the senders, and sending the combination of data units over the communications network on a backup circuit. If one or more link failures occur in the working circuits resulting in loss of one or more of the data units, then the method further includes recovering the one or more of the data units from the combination of data units transmitted on the backup circuit. The backup circuit used to carry the combination of data units may be implemented in-band with user data or may be implemented as out-of-band backup circuits.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority under 35 U.S.C. §119 of a provisional application Ser. No. 60 / 990,179 filed Nov. 26, 2007, which application is hereby incorporated by reference in its entirety.GRANT REFERENCE[0002]This invention was made with government support under Grant No. CNS0626741 and Grant No. CNS0721453 awarded by NSF. The government has certain rights in the invention.FIELD OF THE INVENTION[0003]The present invention relates to network protection.BACKGROUND OF THE INVENTION[0004]One of the important operational requirements of networks is to provide uninterrupted service in the face of failures. This is usually known as network survivability or network resilience, and network service providers consider this requirement to be one of the key requirements that is usually demanded by customers. Depending on the type of the network, and the technology employed therein, failures may be more frequent, and even more catastrophic for on...

AI Technical Summary

Benefits of technology

[0009]It is a further object, feature, or advantage of the present invention to reduce the amount of resources needed to provide network protection.

[0010]It is also an objective, feature, or advantage to recover from the failure as fast as possible, and without invoking management and control plane functionalities.

[0011]Yet another object, feature, or advantage of the present invention is to reduce the costs and effects of failures on a network by providing network protection.

[0012]One or more of these and / or other objects, features, or advantages of the present invention will become apparent from the specification and claims that follow.SUMMARY

[0013]A method for protecting against link failures in a communications network having a plurality of paths between senders and receivers is provided. The method includes sending data units by the senders over the communications network, applying network coding to form a combination of data units from data units from a plurality of the senders, and sending the combination of data units over the communications network. If one or more link failures occur resulting in loss of one or more of the data units, then the method further includes recovering the one or more of the data units from the combination of data units. The combination of data units may be sent in-band with user data or may be sent over one or more backup paths.

Problems solved by technology

1) link failure, 2) node failure, 3) shared risk link group (SRLG) failure, and 4) network control system failure.

Although the common frequent failures are link failures, node failures sometimes happen due to burned switch / router, fire, or any other hardware damage.

In addition, the failure might be due to network maintenance.

However, node failure is more damaging than link or system failures since multiple connections may be affected by the failure of a single node.

However, we provide strategies that utilize network coding and reduced capacity at the source nodes.

However, there will be n−1 equations in n plain data units, which cannot be solved to obtain all missing data units.

Therefore, it is not possible to improve the normalized capacity beyond (n−1) / n.

i) All t link failures happened in the working paths, i.e. working paths have failed to convey the messages in round .

ii) All t link failures happened in the protection paths.

iii) The third case is that the failure might happen in some working and protection paths simultaneously in one particular round in a session.

This lemma shows that one can not provide protection paths better than duplicating the number of working paths.

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